Color Doppler imaging of the ocular ischemic syndrome.

PURPOSE: This study describes hemodynamic characteristics of the ophthalmic, central retinal, and posterior ciliary arteries in 16 eyes of 11 patients with the ocular ischemic syndrome. Understanding the hemodynamic characteristics of the retrobulbar circulation may elucidate the natural history and pathophysiology of the ocular ischemic syndrome and perhaps form the basis for rational treatment of this condition. METHODS: Color Doppler imaging, a procedure that permits rapid noninvasive imaging of the ophthalmic, central retinal, and posterior ciliary arteries, was used to quantitate peak systolic blood flow velocities and vascular resistance (pulsatility index) within these vessels in study group eyes and in an age-matched control population. RESULTS: We demonstrated markedly reduced ocular ischemic syndrome central retinal and posterior ciliary artery peak systolic velocities compared with control group eyes. Central retinal and posterior ciliary artery vascular resistance (pulsatility index) was greater in ocular ischemic eyes versus control group eyes. Reversal of ophthalmic artery blood flow was detected in 12 of 16 ocular ischemic syndrome eyes. Study group eyes with poor vision had no detectable posterior ciliary arterial blood flow. CONCLUSION: Color Doppler imaging quantitates hemodynamic characteristics of the retrobulbar circulation in the ocular ischemic syndrome. There is markedly reduced peak systolic velocity and increased vascular resistance in ocular end arteries such as the central retinal and posterior ciliary arteries. Ophthalmic artery reversal of flow seems to represent collateral blood flow to lower resistance vascular beds. Posterior ciliary artery hypoperfusion may correlate with poor vision in the ocular ischemic syndrome.     

Immune cell imbalance in major depressive and panic disorders.

We investigated subsets of peripheral immunologic cells in 12 drug-free patients affected by major depression according to DSM-III-R criteria, and who had recent evidence of somatic diseases. They were compared with 10 drug-free depressives, with 10 patients with panic disorder, and with 12 healthy volunteers, all without somatic disease. The immune subsets were measured by flow cytometry. The results showed that both groups of depressives had the same abnormalities in immune cells compared with the healthy volunteers or the panic disorder patients; in particular they presented a lower number of CD3+, CD8+ and HLA-DR+. The patients with panic attacks did not differ from healthy controls, except for CD4+ cells which were significantly lowered, even in comparison with the depressive groups. These data, although preliminary and in a small sample, suggest that some immune parameters may be influenced by the presence of a major psychiatric disorder.     

Analysis of thymic epithelial cell proliferation in vitro by combining bromodeoxyuridine and keratin labeling in an immunofluorescence assay

A simple method of analyzing thymic epithelial cell (TEC) proliferation has been developed by combining bromodeoxyuridine (BrDU) and keratin labeling in an immunofluorescence assay. The first reagent specifically visualizes the cells entering the S phase of the cell cycle, whereas the second immunostaining reveals which of the proliferating BrDU-positive cells actually belong to the epithelial lineage. This method, besides being rapid and free of radioactivity, appears to be reliable in view of the minor variations in the percentages of BrDU+ TEC observed in several distinct experiments. Thus, BrDU/keratin immunolabeling appears to represent a useful tool for the analysis of in vitro TEC proliferation.     

Modulation of Cytokeratin Expression in The Hamster Thymus: Evidence For a Plasticity of The Thymic Epithelium

Cytokeratin (CK) expression was investigated, by means of immunocytochemistry, in the hamster thymic epithelium during ontogeny, as well as in primary cultures and upon glucocorticoid hormone treatment in vivo. As compared to the distribution pattern of distinct monoclonal antibody-defined cytokeratins in the normal adult thymus, CK modulation was evidenced in the three situations studied. During thymus ontogeny, both cytokeratins of simple lining epithelia, as CK8 and CK18, as well as the CK1/CK10 pair (typical marker of terminal stage of keratinization), were expressed since early stages of thymus development. They were located in the central region of thymic lobules preceding the cortical-medullary distinctions. This differed from what had been previously shown for mouse thymus ontogeny, revealing that the interspecific diversity in the distribution pattern of thymic cytokeratins occurred early in fetal life. A modulation of CK expression was also detected when hamster thymic epithelial cells (TEC) were led to grow in culture, with a down-regulation of CK19 contrasting with an enhancement of CK18 expression. This diverged from the maintenance of the in situ pattern when human TEC were cultured. Last, in vivo hydrocortisone treatment, known to increase the numbers of KL1⁺ cells in the mouse thymus medulla, promoted a cortical expression of the CK1/CK10 pair in the hamster thymus. Taken together, our findings demonstrate a continuous plasticity of the thymic epithelium, at least regarding cytokeratin expression, and enlarge the concept of interspecific diversity of intrathymic CK distribution in conditions as morphogenesis, in vitro system, and responsiveness to glucocorticoid hormone treatment.     

Properties of a filamentous virus isolated from grapevines affected by corky bark

Summary A virus with highly flexuous filamentous particles c. 800 nm long, showing distinct transverse striations was isolated with high frequency (60%) by inoculation ofNicotiana occidentalis with sap from grapevine accessions indexing positive for corky bark. The virus, for which the name grapevine virus B (GVB) is proposed, has an ssRNA genome with mol. wt. of c. 2.5×10⁶ Da (c. 7600 nt) and coat protein subunits with mol. wt. of c 23,000 Da. GVB has a very restricted herbaceous host range and was experimentally transmitted by the mealybugPseudococcus ficus. The physicochemical and ultrastructural properties of GVB resemble those of closteroviruses. However, it is serologically unrelated to other grapevine closteroviruses including grapevine virus A, with which it shares some biological and physicochemical properties.